Model Perspective

Oct 30, 2026 · Fundamentals

Lean 4 Proof Assistant: Basics, Mathlib, and AI Formalization

This article introduces Lean 4, a functional programming language and interactive theorem prover, covering its dependent type theory foundation, basic syntax with tactics, the Mathlib library, kernel trustworthiness via the de Bruijn criterion, limitations including implementation bugs and statement accuracy, and getting-started resources like the Natural Number Game.